What if we could slow down global warming through reforestation? Newly planted tree seedlings are able to capture and long-term store huge amounts of atmospheric carbon dioxide through the process known as carbon sequestration.

Climate change correlated with trends of temperature rise, decrease in rainfall and in the amount of snow has a wide range of negative impacts on environmental systems, including forests (EEA, 2012). Main causes of climate change could likely be attributed to greenhouse effect, changes in land cover and solar radiations, but also to human activities (Orazio et al., 2013).

According to latest climatic scenarios, drought in Europe will be triggered by changes in temperature and precipitation, correlated with hydrological parameters as river flow; it is highly certain that streamflow drought will intensify in this century, causing higher damages in the frost-free seasons (Feyen and Dankers, 2009). Global warming will reduce minimum flows in river basins by up to 40%, especially in the south of Europe and Balkan regions, while changes in vegetation characteristics will affect evapotranspiration, soil moisture redistribution and groundwater recharge (Forzieri et al., 2014). It is expected that in many parts of Europe the climatic changes will be higher than the global average, while specifically warming gradient patterns can be identified on geographical regions accross the continent (Vautard et al., 2014).

Intergovernmental Panel on Climate Change (IPCC) climate predictions up to 2080 show that mean temperatures will increase on the continent by 1.4-4.5°C, with highest amplitudes in the southern countries, as shown in Fig. 1a (EEA, 2004). Other climatic scenarios indicate that by 2100 the degree of changes in European temperature and precipitation patterns will not be uniform; annual temperatures will increase up to 3°C in the lower latitudes of Europe while the amount of annual precipitations will decrease in central and southern part of Europe but increase in northern areas (Christensen et al., 2007) (Fig. 1b).

Fig. 1(a) Projected temperature (°C) increase by 2080 (Source: EEA, 2004) and (b) temperature and precipitation response to climate change by 2100 in Europe (Source: Christensen et al., 2007)

The levels of greenhouse gases (GHGs) emissions are increasing rapidly in the current development of industrial sector, while a limiting of global warming increase to 2°C compared to preindustrial temperatures as stated by Copenhagen Accord is still questioned (Sanderson et al., 2011). Trends in global carbon dioxide emissions reached a negative record in 2013 with more than 35.3 billion tones (Gt) CO2, an increase of 1.7 % compared to 2012, while average annual increase for 2003-2011 was estimated at 3.8% per year (IES, 2014). Meanwhile, worldwide forests are able to absorb approximately 40% of the total amount of carbon dioxide produced by anthropogenic activities each year (Pan et al., 2011).

Besides the greenhouse effect, global deforestation is also responsible for climate changes. The rate of deforestation is estimated to more than 13 million hectares each year only in the previous decade, caused by forest conversion to other uses or due to natural hazards (FRA, 2010). The main processes on which deforestation emits GHCs are wood burning, especially practiced by farmers, and long term decaying (Bellassen et al., 2008). World forests are storing more than 283 Gt of carbon in their wood, which is more than the amount found in the atmosphere (FRA, 2006). On the other hand, recent reports indicated that deforestation causes between 12-17% of GHGs emissions (IPCC, 2007; van der Werf, 2009), while a previous report pointed out to a higher level of 25-30% (FAO, 2006).

Yet, on the background of ineffective forestry management strategies and natural hazards, carbon sequestration through reforestation could be the solution for reducing GHCs rates.

A study published by Nave et al. (2018) in the scientific journal New Forests on US forests which quantifies the impact of reforestation on ecosystem Carbon pools suggests that reforestation  enhances Carbon sequestration, both in the soil and especially in the woody vegetation, starting immediately and leading to multi-decadal benefits. The research also points out to significant gains in Carbon accumulation for re-planted plots compared to natural regeneration. (Read more about the study here: https://www.nrs.fs.fed.us/pubs/56770).

In conclusion, reforestation could be a useful tools in global warming mitigation, if EU and global strategies on forests would include for the next decades proper measures and programs for increasing forest cover by artificial regeneration.

Main Photo: Puieti Forestieri Ro conifer nursery in Albac, Romania (www.facebook.com/profile.php?id=100009103964274,www.puieti-forestieri.ro/ro/).

References:

1. EEA (2012). Climate change, impacts and vulnerability in Europe 2012. European Environment Agency.
2. Orazio C, Stojnic S, Stojanović D, Gartzia N, Hayes S (2013). The influence of climate change on European forests and the forest sector. www.rokfor.eu.
3. Feyen L, Dankers R (2009). The impact of global warming on streamflow drought in Europe. J Geophys Res 114, doi:10.1029/2008JD011438.
4. Forzieri G, Feyen L, Rojas R, Flörke M, Wimmer F, Bianchi A (2014). Ensemble projections of future streamflow droughts in Europe. Hydrol Earth Syst Sci 18:85-108.
5. Vautard R, Gobiet A, Sobolowski S, Kjellström E, Stegehuis A, Watkiss P et al. (2014). The European climate under a 2°C global warming. Environ Res Let 9.
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9. IES (2014). Trends in global CO2 emissions: 2014 Report. PBL Netherlands Environmental Assessment Agency.
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11. FRA (2010). Global Forest Resources Assessment 2010. FAO.
12. Bellassen V, Crassous R, Dietzsch L, Schwartzman S (2008). Reducing emissions from deforestation and degradation: what contribution from carbon markets?. Climate report 14:1-44.
13. FRA (2006). Global Forest Resources Assessment 2005. Progress towards sustainable forest management. FAO.
14. IPCC (2007). IPCC Fourth Assessment Report: Climate Change 2007 (AR4).
15. van der Werf GR, Morton DC, DeFries RS, Olivier JGJ, Kasibhatla PS, Jackson RB, et al. (2009). CO2 emissions from forest loss. Nature Geoscience 2:737-738.
16. FAO (2006). Deforestation causes global warming. United Nations Framework Convention on Climate Change (UNFCCC), Rome, Italy.
17. Nave LE, Walters BF, Hofmeister KL, Perry CH, Mishra U, Domke GM, Swanston CW. The role of reforestation in carbon sequestration. New Forests doi.org/10.1007/s11056-018-9655-3.
    

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    About the Author:Sorin T. Schiop

    Forestry engineer working in a Romanian forest district. He has a PhD in Genetics and Plant Breeding, with most of the research conducted at the Institute for Plant Molecular and Cellular Biology, Polytechnic University of Valencia, Spain. His expertise includes genetic diversity and biochemical response of Norway spruce seedlings to salt and drought stress, greenhouse and nursery production of conifer seedlings (seed and grafting), forestry management.